Dengue and dengue hemorrhagic fever

In this report, the genomic DNA was examined from two siblings with gonadal LH resistance. A 46,XY pseudohermaphrodite presented with female external genitalia and his 46,XX sister exhibited menstrual irregularities (oligoamenorrhea) and infertility. Exons 1-11 of the LH receptor (LHR) gene were amplified by the PCR using different sets of intronic primers and were directly sequenced. Sequencing revealed that both individuals carried a deletion of nucleotides 1822-1827, resulting in the deletion of Leu-608 and Val-609 within the seventh transmembrane helix. This mutation was introduced into a recombinant human (h) LHR cDNA. Transfections of 293 cells with hLHR(wt) vs. hLHR(deltaL608,V609) revealed that very little of the mutant receptor was expressed at the cell surface. This was due to both a decrease in the total amount of receptor expressed as well as to an increased intracellular retention of the mutant receptor. In spite of the decreased cell surface expression of the mutant, sufficient amounts were present to allow for assessment of its functions. Equilibrium binding assays showed that the cell surface hLHR(deltaL608,V609) binds hCG with an affinity comparable to that of the wild-type receptor. However, the cells expressing the hLHR(deltaL608,V609) exhibit only a 1.5- to 2.4-fold stimulation of cAMP production in response to hCG. In contrast, cells expressing comparably low levels of hLHR(wt) responded to hCG with 11- to 30-fold increases of cAMP levels. Therefore, the testicular and ovarian unresponsiveness to LH in these patients appears to be due to a mutation of the hLHR gene in which Leu-608 and Val-609 are deleted. As a consequence, the majority of the mutant receptor is retained intracellularly. The small percentage of mutant receptor that is expressed at the cell surface binds hormone normally but is unable to activate Gs.     

Kinetic studies on the fragmentation of the third component of complement (C3) by trypsin

The kinetics of cleavage of C3 by trypsin was analyzed by electrophoresis in agarose and in polyacrylamide gels containing sodium dodecyl sulfate and the data obtained were used to construct an anatomical model for C3 showing the sites of tryptic attack, the fragments generated, and their composition. Trypsin was shown to cleave C3 in a stepwise fashion. The attack was initially directed at the alpha-polypeptide chain and resulted in the generation of C3a and C3b. Further cleavage of the alpha-chain of C3b, converted it into C3b1 and then into C3d and C3c. Cleavage of the beta-chain by trypsin occurred only at the C3c stage with the release of a small peptide (m.w. 12,000) from C3c and the formation of C3c'. On immunoelectrophoresis, C3c' had a less anodal mobility compared to the beta1A mobility of C3c. C3a, once formed could be further cleaved to give residual fragments with decreasing net positive charge. Exposure of C3 to acid conditions, pH 5.0 or below, rendered the molecule exceedingly susceptible to tryptic degradation.     

The recetor sites for complement (C3) on human diploid fibroblasts

Sheep red cells, sensitized with 19S fraction of antiserum and subsequently treated with mouse serum as the source of complement (EAC), interact with human diploid fibroblasts (WI-38 cells) and form "Rosettes". Under a scanning electron microscope, EAC have not attached directly to the cell surface of fibroblasts, but to the fine processes or microvilli of the latter, as if there were fine bridges between EAC and the surface of fibroblasts. On the other hand, the attachment of sheep red cells washed in PBS (E) or sensitized with 19S fraction of antiserum (EA) to WI-38 cells was not observed. The pretreatment of WI-38 cells with mouse serum did not inhibit the interaction of WI-38 cells and EAC. No phagocytosis of EAC by WI-38 cells was observed in the 2 hrs incubation of both cells. From these results it is suspected that the interaction of WI-38 cells and EAC is immune adherence, and that WI-38 cells have the receptor site for complement, especially for C3, on the surface of cell membrane.     

Hereditary deficiency in complement C7 and platelet aggregation disorders associated with rheumatoid arthritis. One case (author's transl)

In a patient suffering from rheumatoid arthritis thorough investigations led to the discovery of complete deficiency in the 7th component of the complement. A study of the patient's family tree confirmed the hereditary, codominant autosomal character of the deficiency, unrelated to the HLA system. The complement-dependent serum functions were investigated: the opsonizing and chemotactic activities were preserved, but bactericidal properties were lacking. Coagulation studies showed disorders in platelet aggregation in the presence of thrombin, and these were corrected by the addition of C7. The association of a dysimmune disease with C7 deficiency is probably not fortuitous; it might result from a common gene abnormality or, in some cases, from repeated infections.     

Aseptic isolation of human complement component C3 for in vivo studies

A procedure for aseptic isolation of human complement component C3 is described. The principles may be useful in the preparation of other proteins for in vivo studies.     

Studies on obesity. III. effect of triiodothyronine (T3) on thyroglobulin autoantibodies in euthyroid obese subjects

Effect of T3 therapy on tanned red cell agglutinating thyroglobulin (TRC-TG) antibodies in 10 obese subjects without apparent thyroid disease was investigated. Six other obese subjects without thyroid dysfunction and of approximately the same mean age who also had circulating TRC-TG antibodies served as control subjects and were untreated. In vitro thyroid tests (TSH, total and free T4) performed before T3 therapy, as well as clinical examination, showed thyroid function to be normal in all subjects, and there was no evidence of thyroiditis. TRC-TG antibodies were present in low to moderate titers of 40-1280 in control subjects as well as in subjects selected for T3 treatment. Therapy with T3 was started at 50 mug/day and gradually increased to a maximum of 250 mug/day, depending on clinical needs. T3-treated as well as untreated obese control subjects were all maintained on a high protein, low fat, low carbohydrate diet. Duration of T3 therapy varied from 2-8 mo, and in all but one T3-treated subject, TRC-TG antibodies completely disappeared. In the one exceptional case, TRC-TG antibody titer decreased from 1280 to 80 after 7 mo of therapy. In non-T3-treated obese control subjects, antibody titers remained at the same levels throughout the observation period, thereby indicating a lack of spontaneous regression of circulating immune response. Therapy with T3, by inhibiting TSH, may have caused regression of inapparent immunologic thyroid lesion, thus leading to the disappearance of circulating TRC antibodies; alternatively, T3 specifically may have accelerated catabolism of thyroid antibodies. The latter possibility is favored in the absence of clinical and laboratory evidence of thyroiditis in T3-treated subjects.     

Activated complement component 3 (C3) is required for ultraviolet induction of immunosuppression and antigenic tolerance

Complement component 3 (C3), a critical regulator of innate immunity, may also play a role in the regulation of cognate immunity, such as contact sensitivity responses. Because ultraviolet (UV) radiation also activates C3 in the skin, we determined whether the immunosuppressed state that results when a contact sensitizer is applied through UVB-exposed skin requires the presence and activation of C3. This question was addressed through the use of C3-deficient mice, blockade of C3 cleavage to C3b, and accelerated degradation of iC3b by soluble complement receptor 1 (sCR1). Both C3-modulated systems totally reversed the failure to induce a contact sensitivity response to dinitrofluorobenzene (DNFB) upon primary sensitization at the UV-exposed site, as well as immunologic tolerance to a second DNFB immunization through normal skin. Treatment with sCR1 reduced the infiltration of CD11b+ leukocytes into the epidermis and dermis of UV-irradiated skin but did not reverse the UV-induced depletion of epidermal class II MHC+CD11blo Langerhans cells. These data, taken together with previous results showing abrogation of locally induced UV immunosuppression by in vivo anti-CD11b treatment, suggest a novel mechanism by which ligation of the leukocyte beta2 integrin, CD11b, by iC3b molecules formed from C3 activation in UV-exposed skin, modifies cutaneous CD11b+ cells such that skin antigen-presenting cells are unable to sensitize in a primary immune response, but actively induce antigenic tolerance.     

Emergence of dengue hemorrhagic fever in French Antilles. 3 initial fatal cases in Guadeloupe

BACKGROUND: Two outbreaks of dengue hemorrhagic fever occurred in Guadeloupe (French West Indies) in successive epidemics in 1994 and 1995. The first outbreak was caused by DEN-2 virus and the second by DEN-1. CASE REPORTS: Seven life-threatening infections (WHO grade 3/4) were identified. Three previously healthy adults (including two brothers) died. Autopsy reports (2 patients) disclosed hemorrhagic serous effusions, disseminated intravascular coagulation, and in one case a spontaneous spleen rupture. DISCUSSION: Dengue fever is an emerging disease. Its severe hemorrhagic form tends to an uprising incidence and can no longer be considered a disease limited to children in Far-Eastern Asia. Fatalities may occur very suddenly and unexpectedly, even in optimal health care settings, in healthy adults living or travelling in endemic areas, notably the Caribbean.     

Studies on some lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine

Seven new lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine were synthesized. These complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, FT-IR, electronic and 1HNMR spectra, X-ray powder diffraction, and thermogravimetric studies. The ligand, 4-hydroxyantipyrine （hap）, contained carbonyl oxygen and hydroxyl oxygen as potential donor sites. On coordination, deprotonation occurred and as a result, hap acted as a monobasic bidentate ligand. A coordination number 6 was assigned to the lanthanide（Ⅲ） ions in these complexes with orthorhombic structure. All the complexes were thermally stable-150℃ and underwent decomposition in three stages with the formation of Ln2O3 as the final residues.     

Electrochemical studies on cerium(III) in molten fluoride mixtures

This study aims to determine the principal electrochemical characteristics of the electrodeposition of cerium metal from molten fluoride systems. The cathodic process of Ce³⁺ ions in LiF-NaF and LiF-NaF-CaF₂ molten salts was studied using electrochemical techniques as steady state and cyclic voltammetry methods. The decomposition potential (E_d) and the overvoltage(η) were determined for NaCeF₄ using current-potential curves under galvanostatic conditions. The E_d was found to be 2.025 V in LiF-NaF and 2.045 V in LiF-NaF-CaF₂. It was also found that the ohmic drop potential (EΩ) was not dependent on NaCeF₄ concentration and it rose as the current intensity increased. The overvoltage (η) was determined from the polarization curves and the Tafel coefficients and kinetic parameters were calculated on the assumption that the process constitutes of direct discharge of Ce³⁺, with no solvent-solute interaction. In order to elucidate the cathodic process the investigation by cyclic voltammetry technique was finally used. From the evolution of the voltammograms we concluded that the electrochemical reduction of Ce³⁺ ion was actually a reversible process on the molybdenum electrode and cathodic reduction of Ce³⁺ took place in one single step involving three electron exchanges.     

Molecular analysis of the third component of canine complement (C3) and identification of the mutation responsible for hereditary canine C3 deficiency

Genetically determined deficiency of the third component of complement (C3) in the dog is characterized by a predisposition to recurrent bacterial infections and to type 1 membranoproliferative glomerulonephritis. The current studies were undertaken to characterize the cDNA for wild-type canine C3 and identify the molecular basis for hereditary canine C3 deficiency. Amplification, cloning, and sequence analysis indicated that canine C3 is highly conserved in comparison with human, mouse, and guinea pig C3. Southern blot analysis failed to show any gross deletions or rearrangements of DNA from C3-deficient animals. Northern blot analysis indicated that the livers of these animals contain markedly reduced quantities of a normal length C3 mRNA. The full-length 5.1-kb canine C3 cDNA was amplified in overlapping PCR fragments. Sequence analysis of these fragments has shown a deletion of a cytosine at position 2136 (codon 712), leading to a frameshift that generates a stop codon 11 amino acids downstream. The deletion has been confirmed in genomic DNA, and its inheritance has been demonstrated by allele-specific oligonucleotide hybridization.     

La(C7H5O3)2·(C9H6NO)的合成及热化学研究

研究由七水氯化镧与水杨酸、8-羟基喹啉反应合成镧与水杨酸、8-羟基喹啉多元混合配合物,并对该配合物进行表征.测定该合成反应的标准摩尔反应焓以及配合物的标准摩尔生成焓.通过红外光谱、元素分析、摩尔电导率、差热热重分析以及化学分析等方法来确定配合物的组成.应用溶解量热法分别测定了七水氯化镧、水杨酸、8-羟基喹啉和配合物在298.15 K、混合量热溶剂(VDMFVEtOHVHClO4=110.5)中的标准摩尔溶解焓.通过设计热化学循环,根据盖斯定律计算了合成反应的标准摩尔反应焓以及配合物的标准摩尔生成焓.该配合物的分子式是La(C7H5O3)2·(C9H6NO).各物质的溶解焓分别为△sH(I○)mLaCl3·7H2O(s),298.15 K]=-96.45±0.18 kJ·mol-1,△sH(I○)m[2 C7H6O3(s),298.15 K]=14.99±0.17 kJ·ml-1,△SH(I○)m[C9H7NO(s),298.15 K]=-3.86±0.06kJ·mdl-1及△S(I○)m[La(C7H5O3)2·(C9H6NO)(s),298.15K]=-117.78±0.11kJ·mol-1.反应LaCl3·7H2O(s)+2C7H6O3(s)+C9H7NO(s)=La(C7H5O3)2·(C9H6NO)(s)+3HCl(g)+7H2O(1)的标准摩尔反应焓为91.57±0.33 kJ·mol-1.La(C7H5O3)2·(C9H7NO)(s)的标准摩尔生成焓为△sH(I○)m[La(C7H5O3)2·(C9H6NO)(s),298.15 K]=-2076.5±3.9 kJ·mol-1.     

Comparative studies on Y(III) and Dy(III) extraction from hydrochloric and nitric acids by Cyanex 572 as a novel extractant

Extraction of Y(III) and Dy(III) from hydrochloric and nitric acids by Cy-572 in kerosene was studied. The factors affecting the extraction were separately investigated. The stoichiometry of the extracted species was deduced on the basis of slope analysis method. Evaluation of extraction equilibrium and stripping investigation was studied as well as saponification effect of Cy-572. The composition of the extracted metal species in the organic phase was found to be $\overline{{[\text{MA}}_3·{\left(\text{HA}\right)}_3]}$ for Y(III) or Dy(III) in both media. 1.0 mol/L HCl is the best stripping agent for each metal ion from the studied acidic media in one step. Saponified Cy-572 does not exhibit any selectivity towards the extraction of Y(III) or Dy(III) from both HCl and HNO₃ solutions. Based on the obtained results, the data were compared and the separation feasibility between lanthanides and Y(III) in the two media was discussed.     

Effect of complement (C3) depletion on the generation of memory in rabbits primed with antigens of Trypanosoma evansi

Using the antibody response during secondary exposure of rabbits primed with antigens of Trypanosoma evansi as an indirect measure of immunological memory, it was shown that C3 decomplementaemia resulted in a reduced antibody response, with IgM being predominant in the sera samples followed by IgG and then IgA [corrected]. While significant differences were observed in the levels of IgG produced by the C3-depleted and C3-intact rabbits no differences were recorded in the levels of IgM and IgA produced by the two groups after C3 decomplementaemia. These results demonstrate that C3 depletion did not abolish memory of the T. evansi antigen in these rabbits but only modified the magnitude and pattern of their response. The host response to reinfection may be affected by such changes as those observed in this study.     

Bilayer packing characteristics of mixed chain phospholipid derivatives: Raman spectroscopic and differential scanning calorimetric studies of 1-stearoyl-2-capryl-sn-glycero-3-phosphocholine (C(18):C(10)PC) and 1-stearoyl-2-capryl-sn-glycero-3-phospho-N-trimethylpropanolamine (C(18):C(10)TMPC)

Raman spectroscopy and high-sensitivity differential scanning calorimetry (DSC) were used to compare the effects of headgroup conformation on the acyl chain packing arrangements in two highly asymmetric phosphatidylcholine (PC) analogues, 1-stearoyl-2-capryl-sn-glycero-3-phosphocholine (C(18):C(10)PC) and a polar headgroup derivative of C(18):C(10)PC, 1-stearoyl-2-capryl-sn-glycero-3-phospho-N-trimethylpropanolami ne (C(18):C(10)TMPC), which contains an additional methylene group within the choline moiety; namely, -P-O-(CH2)3-N(CH3)3. The C(18):C(10)TMPC headgroup exhibits an extended trans conformation which is independent of bilayer phase. A comparison of gel phase spectral order parameters of the two lipid species indicates a mixed interdigitated state characteristic of three chains per headgroup for C(18): C(10)TMPC. A more intermolecularly ordered liquid crystalline phase is observed, however, for the C(18):C(10)TMPC bilayers. The phase transition cooperative unit size estimated for the C(18):C(10)PC bilayers (approximately 140 molecules per unit) is about 7-fold greater than that for the C(18):C(10)TMPC dispersions (approximately 20 molecules per unit). We suggest that the extended headgroup for C(18):C(10)TMPC induces a slight tilt in the gel phase packing arrangements for the acyl chains, which may persist in the partially interdigitated liquid crystalline phase bilayer. Macroscopically, tighter packed multilamellar dispersions of C(18):C(10)TMPC occur for systems prepared first in the presence of a higher ionic strength medium. The stacked bilayers may then be transferred to a lower ionic strength environment without loss of their more closely packed adjacent lamellae.     

Studies on the role of platelet eicosanoid metabolism and integrin alpha IIb beta 3 in tumor-cell-induced platelet aggregation

Platelet eicosanoid metabolism resulting from tumor-cell-induced platelet aggregation (TCIPA) was examined in a homologous in vitro system. Rat Walker 256 carcinosarcoma cells induced the aggregation of rat platelets via a thrombin-dependent mechanism with concomitant production of eicosanoid metabolites (e.g., 12-HETE, TXA2). TCIPA was dependent on the concentration of tumor cells inducing aggregation, as well as cyclooxygenase and lipoxygenase products. Cyclooxygenase inhibitors, but not lipoxygenase inhibitors, blocked platelet aggregation induced in vitro by a low concentration of agonist. At a high agonist concentration, neither cyclooxygenase nor lipoxygenase inhibitors alone affected platelet aggregation; however, the combined inhibition of both the cyclooxygenase and lipoxygenase pathways resulted in subsequent inhibition of platelet aggregation regardless of agonist concentration. The extent of platelet TXA2 and 12-HETE biosynthesis was likewise dependent on and correlated with agonist concentration. The inhibitors used in this study did not significantly inhibit protein kinase C activity at the doses tested. Platelet surface glycoprotein alpha IIb beta 3 play an important role in platelet aggregation. The effect of platelet cyclooxygenase and lipoxygenase inhibition in regulating alpha IIb beta 3 surface expression was examined by flow cytometric analysis. Thrombin stimulation of washed rat platelets resulted in significantly increased surface expression of platelet alpha IIb beta 3 integrin complex. The enhanced surface expression was not inhibited by a cyclooxygenase inhibitor (aspirin), a thromboxane synthase inhibitor (CGS-14854) or a thromboxane receptor antagonist (SQ 29,548), nor was it stimulated by a thromboxane A2 mimic (pinane-thromboxane A2). However, alpha IIb beta 3 expression was blocked by lipoxygenase inhibition and stereospecifically increased by the platelet lipoxygenase metabolite 12(S)-HETE. These results suggest that both the platelet lipoxygenase and cyclooxygenase pathways are important for TCIPA but that different mechanisms of action are involved.